Imatinib mesylate, 4-(4-methylpiperazin, 1-ylmethyl)-N-[4-methyl-3-[(4-pyrinin-3-yl)pyrimidin-2-yloamino]phenyl]benzamide mesylate, a compound having the chemical structure,

Imatinib is a protein-tyrosine kinase inhibitor, especially useful in the treatment of various types of cancer and can also be used for the treatment of atherosclerosis, thrombosis, restenosis, or fibrosis. Thus imatinib can also be used for the treatment of non-malignant diseases. Imatinib is usually administered orally in the form of a suitable salt, e.g., in the form of imatinib mesylate.
The present invention relates to the solid-state physical properties of imatinib mesylate. These properties can be influenced by controlling the conditions under which imatinib mesylate is obtained in solid form. Solid-state physical properties include, for example, the flow-ability of the milled solid. Flow-ability affects the ease with which the material is handled during processing into a pharmaceutical product. When particles of the powdered compound do not flow past each other easily, a formulation specialist must take that fact into account in developing a tablet or capsule formulation, which may necessitate the use of glidants such as colloidal silicon dioxide, talc, starch or tribasic calcium phosphate.
Another important solid-state property of a pharmaceutical compound is its rate of dissolution in aqueous fluid. The rate of dissolution of an active ingredient in a patient's stomach fluid can have therapeutic consequences since it imposes an upper limit on the rate at which an orally-administered active ingredient can reach the patient's bloodstream. The rate of dissolution is also a consideration in formulating syrups, elixirs and other liquid medicaments. The solid-state form of a compound may also affect its behavior on compaction and its storage stability.
These practical physical characteristics are influenced by the conformation and orientation of molecules in the unit cell, which defines a particular polymorphic form of a substance. The polymorphic form may give rise to thermal behavior different from that of the amorphous material or another polymorphic form. Thermal behavior is measured in the laboratory by such techniques as capillary melting point, thermogravimetric analysis (TGA) and differential scanning calorimetric (DSC) and can be used to distinguish some polymorphic forms from others. A particular polymorphic form may also give rise to distinct spectroscopic properties that may be detectable by powder X-ray crystallography, solid-state 13C NMR spectrometry and infrared spectrometry.
The present invention also relates to solvates of imatinib mesylate. When a substance crystallizes out of solution, it may trap molecules of solvent at regular intervals in the crystal lattice. Solvation also affects utilitarian physical properties of the solid-state like flowability, dissolution rate, and makes it possible to prepare new forms by the desolvation of solvates.
One of the most important physical properties of a pharmaceutical compound, which can form polymorphs or solvates, is its solubility in aqueous solution, particularly the solubility in gastric juices of a patient. Other important properties relate to the ease of processing the form into pharmaceutical dosages, as the tendency of a powdered or granulated form to flow and the surface properties that determine whether crystals of the form will adhere to each other when compacted into a tablet.
The discovery of new polymorphic forms and solvates of a pharmaceutically useful compound provides a new opportunity to improve the performance characteristics of a pharmaceutical product. It enlarges the repertoire of materials that a formulation scientist has available for designing, for example, a pharmaceutical dosage form of a drug with a targeted release profile or other desired characteristic.
There is a need in the art for new polymorphs of imatinib mesylate and processes for the preparation of imatinib mesylate forms.